You’re probably going to hear this book described as the one that explains how Donald Trump got elected president.

It does, but you’ll need to read more than 400 closely reasoned pages before you reach that point. And by the time you do, Trump’s election may not seem so surprising.

In “Fantasyland,” journalist Kurt Andersen — co-founder of Spy magazine and host of public radio’s “Studio 360” — takes a long look at how we got to the point where we’d elect a bankrupt casino operator, mail-order meat vendor, lewd beauty-pageant huckster and reality TV star to the office once held by Lincoln, Washington and Truman.

The answer, which Andersen develops masterfully, entertainingly and just a bit long-windedly, is that we’ve taken leave of our rationality. As a nation, we’ve given ourselves over to make-believe, thinking more like children than adults.

Andersen traces the blame back to Martin Luther, who made the case that Christians needed no priests, no church hierarchy. Everyone could read the Bible and interpret scripture for themselves. In doing so, Luther planted seeds that would come to full flower 500 years later, when a frightening number of our fellow citizens feel free to believe anything they want to.

“Fantasyland” spends a surprising amount of time on religion, but Andersen obviously thinks it’s key to understanding the American mind.

“America was founded by a nutty religious cult,” he declares. He compares the Puritans to Al-Qaida, refers to “holier-than-thou zealots” and sprinkles in descriptors like “berserk,” “crazified” and “extra-nutty.”

Andersen turns America’s founding story upside down. The real founders of America are the Shakers, the Quakers, the Mormons, the snake handlers, the fire-and-brimstone preachers: in short, the people who took the nation imagined by its rationalist creators and put their own vivid stamp of irrationality on it.

Jumping ahead through the 19th, 20th and 21st centuries, Andersen examines a dizzying array of phenomena, including Buffalo Bill, the Scopes Monkey Trial, Disneyland and the internet.

They all contributed to, in Andersen’s words, “the breakdown of a shared public reality based on widely accepted facts.” Andersen began writing this book long before Trump’s election, but he calls Trump the “apotheosis” of Fantasyland.

“To describe him is practically to summarize this book,” he writes. So there’s your book review: Trump president; America nuts.

John Reinan is a Star Tribune reporter. On Twitter: @StribGuy

By: Kurt Andersen.
Publisher: Random House, 462 pages, $30.